<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        div{/*块级元素特点:独占一行可以修改宽高*/
            width: 100px;
            height: 100px;
            border: 1px solid red;
        }
        span{/*行元素特点:共占一行不能修改宽高*/
            border: 2px solid blue;
            weight: 100px;
            height: 100px;
        }
        img{/*行内块特点:共占一行，可以修改宽高*/
            weight: 100px;
            height: 100px;
        }
        a{
            background-color: green;
            /*行内元素默认不能修改宽高，如果要改则必须将行内元素改为块或行内块元素*/
            display: block;
            width: 100px;
            height: 50px;
        }
    </style>
</head>
<body>
<a href="">超链接</a>
<a href="">超链接</a>
<div>1</div>
<div>2</div>
<div>3</div>
<span>span1</span>
<span>span2</span>
<span>span3</span>
<img src="../b.jpg" alt="">
<img src="j.jpg" alt="">
<img src="../b.jpg" alt="">
</body>
</html>